they absolutely should work on your wifi.  most likely the problem is with the new version of the app (that you use to set the system up).   Lots of things are not working as they should since that update.

I thought surrounds were bonded to the soundbar on a dedicated 5.0GHz link created by the soundbar. Is it different with the Eras? (If not, I wouldn’t think the wifi was the culprit.)

Um maybe.  But you add them as surrounds by sing the “add surrounds” function on the app.  And supposedly you remove them using the “remove surrounds” button in the app.   It when I click “remove surrounds” I get an error message that says “there was a problem removing your surrounds.  Check your network connection and make sure your products are powered on”.  They are definitely powered on.  And working fine as surrounds which makes me think the network connection is fine too,